This invention relates to an automatic welding, cutting, or treating apparatus, and, more particularly, to a robot controlled laser head for welding, cutting, or treating of various materials.
It is generally recognized that, for many purposes, laser beams can provide improved welding, cutting, and treating of various materials. For example, cuts produced by laser beams are generally characterized by a narrow kerf, reduced warpage and decreased risk of fracture of a workpiece, due primarily to the relatively small amount of heat energy absorbed during the cutting operation. These characteristics are particularly significant in the welding, cutting, and treating of high temperature metal alloys.
Also, the use of laser beams for welding, cutting, and treating can result in substantial reductions in hard tooling costs. For example, various workpieces may be placed in a universal fixture and the laser beam then manipulated by a robot or other automatic means. If the robot is capable of recalling programs for each of the various workpieces, the setup does not require changing from workpiece to workpiece. Therefore, short production runs become more cost effective.
However, the use of lasers for industrial purposes has been severally limited by the size and weight of the laser generator required to generate a suitable laser beam for cutting or welding, partly due to the requirements for cooling. For that reason, it has generally been necessary to mount the laser generator in a relatively fixed position and move the workpiece with respect to the laser generator rather than move the laser generator with respect to the workpiece. Such a manipulation of the workpiece is difficult and becomes increasingly impractical as the workpiece becomes larger and heavier.
There has been some experimentation with the use of a flexible fiber-optics tube to transmit a laser beam from a fixed laser generator to a manipulable arm for moving the laser beam relative to a workpiece. However, these uses have been limited to relatively low power laser generators and have been applied primarily to medical applications. Such laser devices have not utilized robots for automatic operation and have not been capable of being scaled up in size for use in industrial applications.
One of the difficulties in employing a flexible fiber-optics tube in an industrial application is the loss of power which results if the tube is subjected to any degree of torsion. No coherent light is transmitted if the fiber-optics tube is twisted. If the laser beam goes "off heat" during welding or cutting, for example, the seam or cut may have an unacceptable discontinuity, causing rejection of the workpiece. For that reason, among others, such a laser-powered device employing a fiber-optics tube in industrial operations has not been practical.
Another problem encountered in using a laser-powered device in industrial applications has been the vulnerability of the lens or other means for focusing the laser beam onto the workpiece. If the lens is jarred out of its precise alignment or is masked by even the slightest amount of dirt, the power of the laser beam will be greatly diminished, further complicating automatic operation. This problem is particularly acute in those industrial environments in which dust and debris are generated.
A need exists for an apparatus which can direct a sufficiently powerful focused laser beam along a desired path relative to a fixed workpiece for performing industrial welding, cutting, or treating of various materials, including high temperature metals. The device should be capable of automatic operation for accurate repetitive performance of industrial operations. And, the device should avoid the expense and bulk of a device in which the laser generator itself is moved over the surface of the workpiece.
Accordingly, it is therefore an object of the present invention to provide an economical apparatus for directing a focused laser beam from a fixed laser generator along a desired path relative to a fixed workpiece, the laser beam being of a sufficient strength to effect commercial welding, cutting, or treating of the workpiece. It is a further object of the present invention to provide such welding, cutting, or treating of the workpiece in an automated manner facilitating low cost, industrial applications.